WO 2008/079057 A1 relates to a safety device in the form of an airbag module which can be mounted to the steering wheel of a motor vehicle. The airbag module has a housing and a cover. The cover is mounted on the housing such that it can move. A wire is clipped onto the cover and configured to come into contact with contact parts, which are arranged on the housing, when the cover is displaced relative to the housing. The wire and the contacts work together as a contact arrangement that can be connected to an electrical circuit which controls the horn of the motor vehicle. If the cover is displaced in the direction of the housing, the wire comes into contact with the contact element and closes the electrical circuit. The contact element is an integral part of the housing which is configured from a metallic, electrically conductive material.
The object of the present invention is to provide a safety device which can be produced more easily and more cost-effectively.
According to the present invention, this object is attained by a safety device having the characteristics described and claimed herein.
The safety device according to the present invention has an airbag module which has a housing and can be mounted in the steering wheel of a motor vehicle, having a cover which is fastened to the housing in a movable manner, on which a first horn contact is arranged, at least a second horn contact is arranged on the housing which is isolated electrically from the first horn contact, and in an activation position, comes into contact with the first horn contact in order to trigger a horn signal. The invention provides that the second horn contact is configured as a separate component, which is fixed to the housing by at least one separate locking element. By configuring the second horn contact as a separate component, for example as a sheet metal component or as an electrically conductive molded part, it is possible to produce the housing from a plastic material, whereby the safety device is in general lighter and less expensive. The risk of faulty activation or electrical short circuits due to a metal housing is prevented. The electrical contact is only established at the contact points provided for that purpose.
The first horn contact can be configured as an electrically conductive wire which is fixed to the cover. The cover normally has a wall extending in the direction of the housing and facing away from the visible side, where the wire can preferentially be fixed to the external side of the wall. It can be clipped in or snapped in; other fastening methods are likewise possible. The wire can at least partially surround the wall of the cover, a resilient contact of the wire with the cover being preferably available.
The housing for accommodating the airbag as well as the gas generator can be made of a plastic material and preferentially completely consists of plastic, so that the housing can be easily and simply produced in a molding process, e.g. by means of injection molding.
The second horn contact can be configured as a conductive ribbon or as a conductive strip, for example made of sheet metal, metal fabric or the like. The locking element can at least have one resilient locking latch that fastens the locking element to the housing in a form fitting manner. The locking latch can engage in a recess or in a form fitting element of the housing, locking holders being configured at the housing which accommodate the locking element in a form fitting manner. The locking holders can for example be configured as frames into which the locking elements are inserted. After inserting the locking latch of the locking element through the locking holder, or through the frame, the resilient locking latch springs back to the initial position and form-fittingly locks the locking element on the locking holder.
The second horn contact can be guided through the locking holders and be fastened to the housing via the locking element. The locking element is preferentially made of plastic and has a front end against which the second horn contact abuts or rests. By supporting the second horn contact on the front end of the locking element facing the first contact of the locking element, the locking element of the second horn contact is not only fastened to the housing, but at the same time functions as a counter bearing and a bearing surface for the second horn contact in the region of the contact point between the first horn contact and the second horn contact. The contact point of the second horn contact is fixed relative to the first horn contact by the locking element so that no displacement of the second horn contact relative to the first horn contact can occur after establishing the electrical contact. Consequently the activation reliability of the horn signal is increased.
In the initial position, the first horn contact preferentially is not separated from the second horn contact by more than 3 mm in the direction of displacement of the cover (for horn actuation), so that only a short displacement path has to be covered relative to the housing in order to trigger a horn signal. By using a separate locking element, it is possible to adjust the contact distance almost arbitrarily without having to consider the requirements when locking and fastening the housing to the cover.